This invention relates to an alignment tool and more particularly to a tool for finding the center of the spaced flanges of a tire building drum which center is on the plane of the perpendicular bisector of the axis of the spaced flanges.
The manufacture of pneumatic tires based on the one stage process or the two stage process (which involves the transferring of a partially built carcass from a first machine to a shaping machine), requires the utilization of a pair of spaced rim flanges. The tire built on the single stage process is fabricated completely on a single tire building drum. In both processes, it is essential that the rim flanges be accurately positioned relatively to each other and the reference point on the machine from which measurements are taken for the tire drum, belts and tread. As the tire is built, the bead portions are supported by the respective rim flanges and the material is placed onto the tire drum including liners, flipper strips, sidewalls, belts and tread. During this construction process, it is essential to center the materials as much as is practical to distribute the material evenly on the tire carcass. As an aid in this construction process, belt guides, centering rings and centerlines are used. Often times, treads and belt materials have centerlines inscribed thereon to facilitate their accurate placement onto the tire carcass. Further, to increase accuracy, projection lights are mounted above the tire machine to project a line onto the tire building drum and the material thereon. In this instance, measurements are made from the projection line and adjustments are made to the rim flanges to assure that the projected line is the centerline of the drum. Alternatively, with the aid of a tape measure, adjustments are made of the rim flanges and the location of the light and its projection. This procedure must be repeated when changing drum sizes to accommodate changes in specification for different tire sizes. The present invention provides a simple centering tool which accurately and quickly defines the center of the flanges. Such centering tool provides rapid means for checking the alignment and positioning of the projector light line. The centering tool provides facile means for accurate focusing the light beam since the point at which the light beam strikes the center position on the tool is automatically adjusted to the height of the material on the drum; since the reference edges intersect at different heights in accordance with the width of the drum and the slope of the reference edges. Such centering tool is inexpensive to make, simple in construction and light weight and is self-aligning to eliminate errors. The fabrication of this tool is simple since two symmetrical pieces of plate can be machined simultaneously and then assembled back to back for use.